Aneroid altimetric device with a



ANERoID ALTIMETRIC DEVICE WITH A HIGH AMPLITUDE FOR AIRCRAFT Sept. l2, 1939. R. BLONDELLE Filed oct. 26, 193e Patented Sept. 12, 1939 UNITED STATES ANEROID ALTIMETRIC DEVICE WITH A HIGH AIVIPLITUDEv FOR AIRCRAFT Roger B londelle, Paris, France Application October 26, 1936, Serial No. 107,743

In France October 29, 1935 l 1 Claim. (Cl. 137-156) My invention relates to an aneroid altimetric device adapted to be used in controlling apparatus carried by an aircraft.

It has already been proposed with a view to 5 securing the operation of apparatus located on board of an aircraft, as Well as of the motor to provide said parts with a correcting device which opposes the effect of the atmospheric depression at high altitudes.

Some devices of that kind, however, are not of a character as to allow the obtainance of satisfactory results by reason of their limited displacement and of their reduced sensitiveness whilst, on another hand, the space occupied by said devices often causes a very important disadvantage.

'Ihe device according to my invention which remedies the above drawbacks comprises in combination a closed tight receptacle having lfor instance a rigid bottom tightly connected with a flexible distortable -non-extensible wall in connection with a piston or like member provided with a return spring with a view to providing a device which may control directly the correction necessary for rendering aircraft able to be used at variable altitudes without the help of additional members or parts. l

My invention also relates to a device in which the tight distortable receptacle constitutes a volume in which exists a pressure conveniently lower than the atmospheric pressure, and the value of which is preferably zero. The device is not aected by the changes of temperature. The

'controlling member of the device is preferably constituted by a spring. Thus external influences arev prevented from affecting the device allowing higher precision to be obtained in the operations while on another hand, the apparatus is Weatherproof. 40 In the accompanying drawing there is shown by way of example two preferred embodiments of my device which are designed for being applied to aircraft and used as regulating apparatus for such purposes as controlling air feed to the pilot of aircraft:

Figs. 1 and 2 show in two diierent positions of operation an axial vertical section of said de- Vice,

50 Figs. 3, and 4 show similar views of another constructional form.

The device comprises a box or receptacle with a rigid end wall l made of metal or any suitable substance and which accommodates on its edge 55 Z a distortable but non-extensible and tight wall 3. 'I'he flexible wall 3 is preferably contained inside the side wall 4.

The distortable wall 3 is secured to `a piston 5 provided with a spring 6 and with a stem 'l which passes freely through a cup 8 whichY con- 5 stitutes an adjustable abutment for the spring 6. The space which is left free between close-d end wall I and distortable wall 3 contains a conveniently elastic fluid which is introduced in said space under a suitable determined pressure. 10'

'I'he pressure is kept under a variable value in all the conditions of operation of the device by reason of the tightness which the device olers by reason of the arrangement of the wall l and distortame wall 3. 15

The piston 5 is suitably shaped for constitutinga support for the distortable wall 3. Such a result may be obtained by providing the piston 5 with a lateral external surface having substantially the same extent as the internal sur- 20 face of the cylindrical wall 4.

Such a device as described above and shown inthe drawing may be used for instance in regulating the feeding of breathable uid to the pilot according to the altitude. gli

For that purpose, the stem l may be connected with any suitable regulating member (not shown in the drawing) and which may be constituted for instance by a needle valve, cock or the like, controlling the pipe which brings a breathable 30 fluid to the pilot. The position of piston 5 is determined by the balance at any time realized for every temperature between the pressure on one of its faces inside the receptacleY formed between the Walls I and 3 and the pressure on its other 35 face exerted by the spring 6, plus the density of the external air at the considered altitude. Such position of piston 5 and of its stem l causes a more or less important flowing of breathable uid to be brought for the pilot according d@ to the altitude.

Near the ground the parts occupy for instance the position of Fig. 1. When the altitude increases, the fluid contained inside the wall 3 actuates piston 5 to the position shown in Fig. 2. 45 l The receptacle or box may be of any desired shape, the transverse cross section may be either circular, oval, polygonal or otherwise formed. 'I'he distortable wall 3 may be made of any suitable material.

The device may be applied directly upon the regulating member to be controlled or it may be connected with said members by means of suitable relays such as electric, mechanical or the like. 65%

It will of course be possible to locate` two or any number of devices in series according to the result to be obtained.

In'the constructional form shown in Figs. 3 and 4, the device comprises as in Figs. l and 2, a rigid end wall I0 receiving on its edge 20 a distortable wall the whole device being contained inside the box.

In this example, however, spring 60 which acts upon piston 50, is located inside the box. The stem 1 fixed to the pistonv passes freelythrough the wall I0 of the protecting box.

In the space existing between end wall l0 distortable wall 30 and piston 50 there is a depression which is conveniently determined relatively to the atmospheric pressure, said depression being in a position to offer any value or even the complete vacuum.

In this arrangement the movements of piston and of its stem 1 takes place under the opposite actions of the atmospheric pressure and of the resilience of spring 60.

It may of course in some events be possible to substitute the compression spring located inside the box for a tractive spring located externally to said box, especially if it is desired to modify the tension of said spring.

Said device may be applied to aircraft as for instance for oxygen apparatus used for pilots or for the regulation of feeding of motors by acting upon the arrival of the liquid fuel to the carburettor. The device may be of course be used as an altimeter in convenient determined condition.

What I claim is:

In an aneroid altimeter for controlling apparatus carried by an aircraft, a receptacle having a substantially cylindrical shaped wall, a rigid end wall closing one end of the receptacle, a piston movable in the receptacle, a flexible nonextensible member secured to the piston head and connected to the wall of the receptacle adjacent said end wall to provide a closed space between the flexible member and the end wall, a stem xed to the piston extending axially therefrom, a threaded cup member closing the other end of the receptacle and having an opening therein through which said stem extends, and a spring surrounding said stern engaging said piston and said cup member.

' ROGER BLONDELLE. 

